The following relates generally to wireless communication, and more specifically to flexible comb-based reference signals.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system, or a New Radio (NR) system). A wireless multiple-access communications system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, that may be otherwise known as user equipment (UE).
In some wireless communications systems, such as LTE or LTE-Advanced (LTE-A), an uplink demodulation reference signal (DMRS) is transmitted by a UE to a base station via a physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH). The base station may estimate channel parameters based on the received DMRS. The uplink DMRS may occupy all tones (i.e., subcarriers) of an allocated bandwidth for the transmission. If a UE is transmitting using the PUCCH, the UE may implement a computer generated sequence to transmit the DMRS. However, some devices (e.g., multiple-input, multiple-output (MIMO) devices) may not support transmission of a DMRS using the PUCCH.